1. Field of the Invention
The present invention relates generally to a method and apparatus for installing earth anchors and more particularly to a method and apparatus for installing earth anchors using a rotating power source for driving a torque tube through a drive coupling for detachably interconnecting the power source with the torque tube and an anchor being driven.
2. Description of the Prior Art
U.S. Pat. Nos. 3,832,860 and 3,832,861 disclose a method and apparatus for installing earth anchors. U.S. Pat. No. 3,148,510 discloses a method of installing earth anchors and U.S. Pat. No. 3,377,077 discloses a power installed screw anchor wrench. Other U.S. patents of interest are Widmer, No. 816,631; Lucas, No. 923,056; Kammerer, No. 2,758,891; Decker, No. 2,775,889; Yager, No. 3,525,225; Marcus, No. 3,529,460 and Petres, No. 3,828,562.
Many prior art systems for power driving screws anchors into the earth have disadvantages such as locking dogs which are difficult and cumbersome to advance and retract. Such prior art locking dogs make it difficult to secure a torque tube wrench and an anchor guy rod in place during installation and in addition make it difficult to release the anchor and torque tube after installation is completed.
Another disadvantage of prior art systems is the fact that it is often difficult to ascertain visually or otherwise whether or not the locking dogs are in a particular position such as an engaged position or a disengaged configuration for releasing the torque tube or the anchor, or both. Moreover, high values of force are often required in order to release the locking dogs after an anchor has been installed so that the torque tube may be withdrawn from the anchor. In addition, subsequently after withdrawal of the torque tube from a driven anchor it is some times difficult to get the torque tube released from the drive adaptor when desired.